In today's environment, there are many hazardous conditions that may exist. Some of these hazardous conditions are attributed to equipment failure where there is a fault as a result of incomplete combustion of natural gas, which can result in the undesirable atmosphere of carbon monoxide gas.
Other hazards may include the inadvertent release of combustible gases, such as, propane, methane, hydrogen or natural gas, which when released into the atmosphere can create a hazardous explosive environment. The risk of creating an explosive atmosphere increases substantially when these gases are mixed with the oxygen found in air.
Still other hazards can be created by natural cataclysmic events, such as, earthquakes that can shift the foundation of buildings and residences, causing pipelines and pipeline connections to rupture and leak to the atmosphere.
Some other hazards can be created by accident. Hazardous conditions have been created in events where, for example, an automobile careens into a gasoline pump in a gas station, shearing it off, causing a substantial amount of gasoline to be released into the surrounding area.
Many systems that function to close the flow of a fluid substance do not provide for stored energy to operate an actuator during a cataclysmic event, such as caused by fire or flooding.
There is a particular need for apparatus that will rapidly and reliably shut down the flow of a product, such as a fluid, liquid or gas, into the atmosphere in the event of an accidental or even a natural cataclysmic disaster to protect life and property.
There are several patents that disclose various pneumatically or hydraulically operated actuators that are used to remotely control and operate these valves.
U.S. Pat. No. 5,211,195, granted May 18, 1993, to R. E. Hamos, discloses a fluid valve having a valve housing defined as a corner. The valve opening is initiated by moving the pilot valve away from the aperture in the expandable valve closing member, and as such, the opening of the valve is completed by pulling the expandable valve closing member away from its valve seat.
U.S. Pat. No. 5,181,452, granted Jan. 26, 1993, to G. Immega, discloses a linear bellows actuator that is expandable and contractible along the axis by flexure of the wall portions relative to one another about the fold lines in response to the pressure changes occurring within the bellows chamber.
U.S. Pat. No. 5,101,862, granted Apr. 7, 1992, to B. C. Leete, discloses a hydraulic oscillatory rotary actuator for controlling an adjustable valve. The chamber housing and the chamber wall form a rotary chamber for the arcuate movement of the depending vane or rotary piston.
As can be seen from the discussion of the previous prior art, a specialized need exists for a safe and reliable pneumatically actuated valve actuator that uses its own standby pressure source which can be remotely operated even during a power failure.